package com.example.sqlite3;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;

public class MyDatebaseHelper extends SQLiteOpenHelper {
    public static final String CREATE_BOOK = "create table Book("
            + "id integer primary key autoincrement,"
            + "author text,"
            + "price real,"  // 浮点型
            + "pages integer,"
            + "name text)"; // 文本类型

    public static final String CREATE_CATEGORY = "create table Category ("
            + "id integer primary key autoincrement,"
            + "category_name text,"
            + "category_code integer)";


    private Context mContext;

    public MyDatebaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context,name,factory,version);
        mContext = context;
    }

    /**
     * 数据库创建的时候，才执行
     * 如果数据库已经存在，将不会执行这个方法
     * @param db
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        // 执行sql语句
        db.execSQL(CREATE_BOOK);
        db.execSQL(CREATE_CATEGORY);
        Toast.makeText(mContext,"Create succeeded",Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("drop table if exists Book");
        db.execSQL("drop table if exists Category");
        onCreate(db);

    }
}
